Tyagi arrived at CBI headquarters at around 10 am for questioning. The Milan Court of Appeals -- equivalent of an Indian high Court -- has given details of how alleged bribes were paid by helicopter-maker Finmeccanica and AgustaWestland to Indian officials through middlemen to clinch the deal.

The order mentions the name of Tyagi at several points. CBI had registered a case against Tyagi along with 13 others including his cousins and European middlemen in the case.Also read: AgustaWestland issue: How it all startedThe allegation against the former Air Chief was that he had reduced flying ceiling of the helicopter from 6,000m to 4,500m (15,000ft) so that AgustaWestland was included in thebids.

However, this decision was reportedly taken in consultation with the officials of SPG and the Prime Minister's Office including then NSA M K Narayanan.

CBI has alleged that the reduction of the service ceiling--maximum height at which a helicopter can perform normally--allowed the UK-based firm to get into the fray as otherwise its helicopters were not even qualified for submission of bids.Also read: AgustaWestland Chopper deal: Defence Minister Parrikar to place facts in Parliament on 4th MayCBI which has received a copy of the Milan court order has now prepared a fresh set of questionnaire to put to Tyagi. Tyagi has denied allegations against him and has claimed that the decision to reduce the ceiling was taken by a group of senior officials.

The agency had already questioned Tyagi but this session is the first after the Italian court order. His cousins have also been called by the agency.